I'm reading Japanese Sentence Patterns for Effective Communication,and I'm currently at the chapter describing Both-noun-and-noun-sentences, as well as neither-noun-nor-noun-sentences. However, some of the examples are confusing me a little bit.

One example of neither...nor goes like this:ジムもサムもフットボールの選手じゃない.Neither Jim nor Sam is a football player.

Why is there a で in one of the examples? Is it because it's formal, like an equivalent of ではありません/ではない? That's what I thought, but I'm not 100% sure.

Hello there fellow Swede and welcome to TJP! The difference is that in the first sentence ジム and サム are the topic of the sentence. In this case the second も is basically the same thing as a は. In the second sentence 妹 is the topic, and the rest of the sentence lists what she isn't, using the ではありません construction. In this case the は in ではありません is replaced with も and the first では is replaced with でも to make it list more than one thing that 妹 is not.

I'm sorry that I can't explain it better than this. Someone else might swing by and explain it better than I can. What I can do for you though, is to give you a couple of example sentence and see if you can work out the grammar yourself.

ボブはお金も食べ物もないのでとっても困っています。Bob is in trouble because he doesn't have any money or food.

田中さんは医者でも看護師でもないのに、街の中で倒れていたおじいさんの命を見事に救ってくれました。Tanaka-san is neither a doctor, nor a nurse, yet he/she managed to save the life of an old man who had fainted on the street(liberal translation of 街).

村上さんも大久保さんもフランス語が全然話せないから、パリに行ったときに地元の人とはろくに話せませんでした。Since neither Murakami-san or Ookubo-san can speak French at all, they weren't able communicate well at all with the locals when they went to Paris.

Why is there a で in one of the examples? Is it because it's formal, like an equivalent of ではありません/ではない? That's what I thought, but I'm not 100% sure.

Hello there fellow Swede and welcome to TJP! The difference is that in the first sentence ジム and サム are the topic of the sentence. In this case the second も is basically the same thing as a は. In the second sentence 妹 is the topic, and the rest of the sentence lists what she isn't, using the ではありません construction. In this case the は in ではありません is replaced with も and the first では is replaced with でも to make it list more than one thing that 妹 is not.

I'm sorry that I can't explain it better than this. Someone else might swing by and explain it better than I can. What I can do for you though, is to give you a couple of example sentence and see if you can work out the grammar yourself.

ボブはお金も食べ物もないのでとっても困っています。Bob is in trouble because he doesn't have any money or food.

田中さんは医者でも看護師でもないのに、街の中で倒れていたおじいさんの命を見事に救ってくれました。Tanaka-san is neither a doctor, nor a nurse, yet he/she managed to save the life of an old man who had fainted on the street(liberal translation of 街).

村上さんも大久保さんもフランス語が全然話せないから、パリに行ったときに地元の人とはろくに話せませんでした。Since neither Murakami-san or Ookubo-san can speak French at all, they weren't able communicate well at all with the locals when they went to Paris.

Sorry I can't help more!

God jul och gott nytt år

Thank you for your welcoming, as well as for your help! I appreciate all help that I can get. =D

You say that the difference is that in the first sentence ジム and サム are the topic of the sentence, but in one of your example sentences, the one with Bob, neither お金 or 食べ物 are the topic, right? So why do they get a simple も? Edit; Is it because they are replacing the particle ga?

I thank you for all your help! You have no obligation to help me, so I'm very grateful.

To us, this sort of “で” alone, which is a stem of です or である, looks almost equal to です or である.Which means, お金 で も ない can be parsed like: mony-is-too-not(What Bob wants) - is – not – money – too.On the other hand, in ボブはお金も食べ物もない sentence, there is no で stem.

To us, this sort of “で” alone, which is a stem of です or である, looks almost equal to です or である.Which means, お金 で も ない can be parsed like: mony-is-too-not(What Bob wants) - is – not – money – too.On the other hand, in ボブはお金も食べ物もない sentence, there is no で stem.

It does matter, which you would use depends on the context. If you would put です/ではありません after the word in a simple sentence, you would use でも(あります/ありません) in a compound both/neither sentence. If not, you use simply も.

It helps to understand that the original form of the copula だ is である (well, it's actually not the original form, but let's not get into Old/Classical Japanese...), which you will still find in use in academic writing and such. (It's very common on the Japanese Wikipedia, for instance.) You can think of the で in である as a particle; the main verb is ある. If you negate である, you get でない, which you see sometimes, but you see it much more often with the topic particle interposed, giving you ではない (in polite conjugation, ではありません). The informal negative copula じゃない is a contraction of ではない.

So! Let's make some sentences.妹はピアニストである。My sister is a pianist.

妹はピアニストで歌手である。My sister is a pianist and a singer. Think of this as being like "ピアニストである and 歌手である" -- both ピアニスト and 歌手 are connected to ある with で.

Anyway, in everyday usage, you would use だ instead of である in the first two sentences, but remember だ is just a contraction of である; you're just using uncontracted forms (since no contractions are possible) when you say things like でもある and でもない.